Mandrel for vulcanizing tire-shoes.



H. Z. CMS. Mmmm ma www ZENG APPLICATIGN HLED ULY 3 Patmted Dee, 4@ 7.

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2 SHEETS- H. Z. CUBE.

MANDHEL Fon vuLcANlzmG NRE SHOES.

4 APPLICATION FILED IULY 3, 5914. LQQB precisionizing an p y Leashes.

HENRYl Z. CIBB, 0F WINCHESTER, MASSACHUSETTS, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, T0 UNITED STATES RUBBER COMPANX, OF NEW BRUNSWICK, NEW JERSEY, A. CORPORATION 0F NEW JERSEY.

` MANDREL FOR VULCANIZING TIRE-SHOES.

To all. 'whom t may concern.'

Be it known that I, HENRY Z. C oBB,.a citizen ofthe United States, residing in Winchester, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Mandrels for Vulcanizing Tire-Shoes, of which the following is a specification.

r[his invention relates to the manufacture of tire shoes or casings for pneumatic vehicle tires, and has for an object to provide a duid pressure chamber within the mandrel, the pressure of which is thermostatically released to the interior of the shoe upon the mold, and also provides a sectional or segmental mandrel rovided with means for locking the sections in position, which mandrel is readily assembled prior to the application of the shoe thereon and may be readily disassembled preliminary to its removal from the finished shoe.

in theV manufacture of shoes or casings for pneumatic vehicle tires, it is customary te build up the successive layers thereof on a ring-shaped core or mandrel to which on the exterior the rubber cushionis applied, and then to place the mandrel with its raw shoe in a mold assembling a series of such molds held together under suitable pressure in a vulcanizing oven, and therein subJecting them to heat for vulcanizing the tire lill shoesf` in this operation it is difhcult to insure so close a lit between the raw shoe and the material of the mold as to cause the shoe to completely fill all the interstices of the mold and take a full imprint therefrom. ln order to expand the shoe forcibly within the mold, Huid pressure has been introduced into it and maintained during the vulcanizingrthis, however, is subject to the disadvantage that it is necessary to couple pipes leading from a source of compressed air to the respective mandrels or mold sections, and to maintain these pipes and couplings in non-leaking condition during the WL canizing period, which in practice involves much difficulty.

My present invention provides for eirpanding the tire shoe into the mold by fluid pressure in the form of gas or vapor which Specification of Letters Patent. Patented Dee, 4, 191'?,

Application iiled July 3, 1914. Serial No. 848,767.

is admitted from a suitable chamber to the interior of the shoe to press the latter outwardly into intimate contact with the mold. Thus instead of having a source of pressure which is connected through coupling means to the respective mandrelsfor mold sections,

each mandrel is providedr with its own source vof fluid pressure.` For this purpose means, so that a tight joint is made between the shoes and the molds.

The admission of the pressure to the shoe is best determined thermostatically. The gas or vapor under pressure is of determinate volume depending upon the charge previously introduced into the chamber. The chamber is preferably a hollow iny the` mandrel. Preferably air is forced into the chamber to a given pressure, being confined therein until liberated by the action of the thermostatic means, which is a thermostatically actuated valve or a fuse plug.- Or a vaporizable liquid such as Water may be introduced in measured volume into the chamber, so that on the opening of the thermostatic plug or valve the vulcanizing heat will vaporize the water and generate the required pressure within the shoe.

In the drawings accompanying this specification a practicable embodiment of the invention is illustrated, in whichdrawings- Figure l represents a side elevation of my improved mandrel, a portion of the broken* away tire being shown mounted upon the mandrel.

Fig. 2 is a larger cross-section taken on a plane at about the line 2-2 of Fig. 1.

Fig. 3 is a similar cross-section of fthe mandrel taken on a plane at about the line 3 3 of Fig .ind also represents a crosssection of a shoe in position on the mandrel, and a cross-section of a mold investing the whole.

Fig. 4 is a central section of the segments of the mandrel, the retaining ring having been rempved therefrom, one of the segments, the .key segment, being shown displaced from the others.

Fig. 5 is a side 'elevationofthe ring.

Fig. 6 is an edge view thereof.

Fig. 7 is an enlarged sectional detail of the end of one of the segments, illustrating .the admission valve for the compressed Huid therein.

Fig. 8 is an end view of the admission valve.

Fig. 9 is an enlarged edge view of the mandrel, viewing the same from the outer edge.

Fig. 10is a similar view, looking at the inner edge, the ring being removed.

Figfll is a cross-section of the mandrel, illustrating a form of thermostatic valve.

The mandel is shown made up of hollow segmental sectiorgs a a and a short segmental section bythe section b acting infthe nature of a key for holding the other sections in position. The sections a a and b are shown united by a ring c within them having some suitable means for attachment therewith. In the present illustration the segments are shown provided with tapering dove-tailed grooves and projections a a2, and the ring is shown provided with tapering dove-tailed grooves and projections c c2. The dove-tails serve the purpose of securing the segments together, and of positioning and precisionizing the entire mandrel. Each segment a being made hollow has a chamber d within it. An inlet check valve e of some suitable construction is applied through which to force air or other gas into the chamber d.' This valve may be of any usual construction of tire valve, a simple form being that illustrated. The tapering valve e is shown seating in a plug e2, pressed to its seat by means of a spring c3, surrounding the valve stem e4 which is guided by the yoke e5. An inlet pipe e is shown temporarily connected to the plug e2 for supplying uid under pressure from some suitable source not shown.

Each segment a has a thermostatic outlet valve f preferably of the simple construction illustrated in Figs. 2 and 4, wherein a cork g which maybe of rubber is forced tightly into a hole, and a dove-tailed chamber above it is filled with molten parain or other wax to form a fusible plug h. Another form of valve is illustrated in Fig. 11, wherein the valve f is shown of conical formation and pressed toward its seat f2 by means of a coiled spring f3 surrounding the valve stem f* and engaging the yoke f5. The outer portion of the outlet from the hollow chamber d to this is closed by means of a plug f6 having suitable air passages through it. The end of the valve f is shown carrying a plug f7 of some expansible material, preferably copper, which engages the plug f". The expansion of the plug f7 will unseat the valve and permit the luid under pressure in the chamber d to escape past the valve and valve seat.

The mold B is shown of usual construction, being of annular form and divijded centrally so as to form equal halves as shown in Fig. 8.

As best shown in Fig. 2 the mandrel has an annular neck portion or inner flange m presenting flat faces on opposite sides flush with the iat side faces of the ring c. The mold being correspondingly shaped, it is only necessary to extend the inner lining n of the shoe which is of soft rubber inwardly to cover these flat faces, in order thereby to utilize this lining as' a packing for making a tight joint between the mold and the mandrel when the faces of themoldl are clampedtightly together by the usual means (not shown). To give further assurance of making an air-tight fit, the neck portion m and the ring o (or either of them) are formed with one or more annular groovesp g, as best shown in Fig. 2, into which grooves the soft rubber of this lining enters under heat and pressure and affords an effectual seal against the escape of the air or other fluid.

The described method of manufacturing tire shoes is set forth in detail in a companion application which illustrates and de-- scribes the mandrel made the subject of the present application.

In using the improved mandrel the segmental sections a a b are placed in proper position. They may be heldin alinement by means of suitable keys r fr. The sections, of course, are to be united after the fluid within the chamber d has been brought to the proper stage of compression, if the compression valves are located at points which are inaccessible after assemblage, as in the present illustration. It is advantageous to have the admission valves so located to prevent accidental unseating of the valves. After the segments have been properly brought together, the ring c will be forced into position, and by means of the tapering dove-tails the segments Will be positioned,

and locked and 'securely heldin position. After this the shoe will be built up in any approved manner. This is then placed in a mold which is shaped interiorly to give the proper form and pattern to the exterior of the shoe. The segments of the mold are held together in some suitable manner. The thermostatic valve is preferably adapted to open under a temperature for example of The molds are placed in some suitable 130 vulcanizing oven or chamber, and this is heated up to the customary vulcanizlng temperature and the vulcanlzing operation is conducted in precisely the ordinary manner. On reaching the prescribed temperature the thermostatic valves in the mandrel sections open and permit the compressed air to blow out from the chambers into the shoe, thereby lifting the shoe away from the mandrel, and expanding it outwardly against the inner face of the mold and holding it there during the vulcanizing operation. An air-tight joint is assured by the usual inner 'lining of. sofl-rubber extending between the inner part-or neck ofthe mandrel and the `corresponding faces of the mold, so that this forms a packin to seal the joint between these res ective aces'and thereby prevent escape o the compressed air.

Instead of using air or other fixed gas,

vapor may be provided by introducing intothe chamber d a quantity of Water or" other vaporizable liquid, choosin vapor of which Willnot a ect the rubber of the tire shoe. A predetermined.. uantity of liquid will be introduced such t at under the vulcanizing temperature the vapor tension will aord vthe required pressure.

It will be apparent that changes in details of construction may be made within the terms of the claims without departing from the spirit of the'invention.

I claim as my invention 1. A tire shoe mandrel comprising a` plurality of segments, and a ring within them for holding them in proper relative positions, the abutting approximately cylindrical surfaces of the ring and segments being varied to form dove-tails extending across the plane of the mandrel.

2. 'A tire shoe mandrel comprisinga plurality lof segments provided on then' inner faces with tapering dove-tails, and a ring for holding said segments -in proper relative positions and provided on its periphery with tapering dove-tails mating with those on said segments, said dove-tails extending across the plane of the mandrel and tapered tQtighten as the ring is moved toward such plane. f,

-1- 3. Aftire shoe mandrel comprisin a plu- V-rality of segments, keys for alining `the segments at their abutting ends, and a ring located within said segments, there being mating dove-tails transverse to the plane of the ring formed on the segments and ring.

4. A tire shoe mandrel comprising a hollow body having formed within it a chamber adapted to receive and confine a charge of fluid, and having an admission valve to such chamber, and a thermostatic discharge valve opening from such chamber. f

5. A mandrel comprising a plurality of connected segments, some of said segments a liquid the face between which and such being hollow bodies, each lof'fwhich" comprises a chamber adapted to contaln; a charge of uid under pressure, Van admission valve to such chamber, a dischar ey valve from such chamber, and thermostatl'c means for controlling said discharge .valve.i

6. A mandrel comprisin a pair of hollowj' segments, each having wit in it a chamberv for receiving a charge of fluid under pres-l' 7 A mandrel comprisin a pair' of hollvvI segments, each havingwit it a chamber for vrece1ving a charge of fluid. under pressure, said segments abutting each other at.

one end, a key segment located between'the said segments and abutting the free` ends thereof, an admission valve in the free end of each such segment, a discharge valve in' the mandrel face of each said segment, and

'thermostatic means for .controlling u said discharge valves. l Y.

8. A tire shoe mandrel comprising a plurality of segments, and a ring within them for holding the segments in roper relative positions, the segments having an inner neck portion abutting said'ring and flush therewith to form therewith a packing surface and a mold having a conforming surpacking surface to confine a packing.

9.V A tire shoe mandrel comprising a plurality of segments, and a ring within them for holdin the segments in proper relative positions, t e segments having an inner neck portionv abutting said ring to form therewith a packing surface, and having grooves in said pa'ckin surface.

10. A man rel formed with a chamber adapted to confine fluid under pressure, such chamber having a thermostatic closure adapted to open and liberate the confined fluid under vulcanizing conditions.

11. A mandrel formed with an individual chamberadapted to conine a source of fluid pressuresuitable for expandin within the mold only the one tire shoe to e vulcanized on such mandrel, and havin means rality of connected segments, one of said In witness whereof, I have hereunto segments having formed therein a chamber signed my name in thepresence of two subadapted to confine a fluid under pressure scrbing Witnesses. sucient to expand within the mold the one 5 tire shoe on such mandrel, and having' Witnesses:

means adapted to liberate such conned B. L. MARTIN, fluid during the vulcanizing operation. A. T. MARTIN.

HENRY Z. COBB.

copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patentip wumngumno. v 

